Django——图书管理系统（七）

from django.shortcuts import render, redirect, HttpResponse
from app01 import models


# Create your views here.


def publisher_list(request):
    obj = models.Publisher.objects.all()  # 获取所有对象
    return render(request, 'publisher_list.html', {'publisher_list': obj})  # {'publisher_list': obj}是模板，可以传递给前端页面。


def publisher_add(request):
    if request.method == "POST":  # 如果是POST请求
        pub_name = request.POST.get('pub_name')  # 获取出版社的名称
        if not pub_name:
            return render(request, 'publisher_add.html', {'error': "出版社名字不能为空"})
        if models.Publisher.objects.filter(name=pub_name):
            return render(request, 'publisher_add.html', {'error': "出版社已经存在"})
        models.Publisher.objects.create(name=pub_name)  # 增加出版社，使用create方法
        return redirect('/publisher_list/')  # 增加完成以后，跳转到获取所有出版社页面
    return render(request, 'publisher_add.html')  # 默认返回增加页面。


def publisher_del(request):
    pk = request.GET.get('id')  # 获取URL中id字段的值
    models.Publisher.objects.filter(id=pk).delete()  # 删除数据库中的数据
    return redirect('/publisher_list/')  # 重定向页面。


def publisher_edit(request):
    id = request.GET.get('id')
    obj1 = models.Publisher.objects.get(id=id)
    if request.method == "GET":
        return render(request, 'publisher_edit.html', {'pub_obj': obj1})
    else:
        name = request.POST.get('pub_name')
        obj2 = models.Publisher.objects.filter(name=name)
        if obj2:
            return render(request, 'publisher_edit.html', {'msg': "该出版社已存在"})
        else:
            obj1.name = name  # 在内存中修改
            obj1.save()  # 将修改保存到数据库
            return redirect('/publisher_list')  # 重定向到list页面


def book_list(request):
    objs = models.Book.objects.all()

    # for obj in objs:
    #     print(obj.name)
    #     print(obj.publisher.name)       # 关联出版社的名字
    #     print(obj.publisher)            # 书籍所关联的出版社对象
    #     print(obj.publisher_id)         # 通过_id可以直接拿到关联的出版社的id
    #     print("\n")

    return render(request, 'book_list.html', {'objs': objs})


def book_add(request):
    if request.method == "GET":
        pub_obj = models.Publisher.objects.all()
        return render(request, 'book_add.html', {'pub_obj': pub_obj})
    elif request.method == "POST":
        book_name = request.POST.get('book_name')
        pub_id = request.POST.get('pub_id')
        if not book_name:  # 书名为空
            pub_obj = models.Publisher.objects.all()
            return render(request, 'book_add.html', {'pub_obj': pub_obj, 'err_msg': '书名不能为空'})
        if models.Book.objects.filter(name=book_name):  # 书籍已存在
            pub_obj = models.Publisher.objects.all()
            return render(request, 'book_add.html', {'pub_obj': pub_obj, 'err_msg': '书籍已存在'})
        # models.Book.objects.create(name=book_name, publisher=models.Publisher.objects.get(id=pub_id))         #两种方式

        models.Book.objects.create(name=book_name, publisher_id=pub_id)
        return redirect('/book_list/')
    else:
        return HttpResponse("请求方式错误")


def book_del(request):
    if request.method == "GET":
        book_id = request.GET.get('id')
        obj = models.Book.objects.filter(id=book_id).delete()
        return redirect('/book_list/')
    else:
        return HttpResponse("请求方式错误")


def book_edit(request):
    book_id = request.GET.get('id')
    obj = models.Book.objects.get(id=book_id)
    pub_obj = models.Publisher.objects.all()
    if request.method == "GET":
        return render(request, 'book_edit.html', {'obj': obj, 'pub_obj': pub_obj})
    elif request.method == "POST":
        book_name = request.POST.get('book_name')
        pub_id = request.POST.get('pub_id')

        # 方式一
        # obj.name = book_name
        # obj.publisher_id = pub_id
        # obj.save()  # 保存到数据库中

        # 方式二
        models.Book.objects.filter(id=book_id).update(name=book_name,
                                                      publisher_id=pub_id)  # 实际上filter返回的是一个列表，理论上是此时的update是一个批量操作。
        # 这个update是
        return redirect('/book_list/')
    else:
        return HttpResponse("请求方式错误")